1 //===-- lib/Evaluate/fold-real.cpp ----------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "fold-implementation.h"
10 
11 namespace Fortran::evaluate {
12 
13 template <int KIND>
FoldIntrinsicFunction(FoldingContext & context,FunctionRef<Type<TypeCategory::Real,KIND>> && funcRef)14 Expr<Type<TypeCategory::Real, KIND>> FoldIntrinsicFunction(
15     FoldingContext &context,
16     FunctionRef<Type<TypeCategory::Real, KIND>> &&funcRef) {
17   using T = Type<TypeCategory::Real, KIND>;
18   using ComplexT = Type<TypeCategory::Complex, KIND>;
19   ActualArguments &args{funcRef.arguments()};
20   auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)};
21   CHECK(intrinsic);
22   std::string name{intrinsic->name};
23   if (name == "acos" || name == "acosh" || name == "asin" || name == "asinh" ||
24       (name == "atan" && args.size() == 1) || name == "atanh" ||
25       name == "bessel_j0" || name == "bessel_j1" || name == "bessel_y0" ||
26       name == "bessel_y1" || name == "cos" || name == "cosh" || name == "erf" ||
27       name == "erfc" || name == "erfc_scaled" || name == "exp" ||
28       name == "gamma" || name == "log" || name == "log10" ||
29       name == "log_gamma" || name == "sin" || name == "sinh" ||
30       name == "sqrt" || name == "tan" || name == "tanh") {
31     CHECK(args.size() == 1);
32     if (auto callable{GetHostRuntimeWrapper<T, T>(name)}) {
33       return FoldElementalIntrinsic<T, T>(
34           context, std::move(funcRef), *callable);
35     } else {
36       context.messages().Say(
37           "%s(real(kind=%d)) cannot be folded on host"_en_US, name, KIND);
38     }
39   } else if (name == "amax0" || name == "amin0" || name == "amin1" ||
40       name == "amax1" || name == "dmin1" || name == "dmax1") {
41     return RewriteSpecificMINorMAX(context, std::move(funcRef));
42   } else if (name == "atan" || name == "atan2" || name == "hypot" ||
43       name == "mod") {
44     std::string localName{name == "atan" ? "atan2" : name};
45     CHECK(args.size() == 2);
46     if (auto callable{GetHostRuntimeWrapper<T, T, T>(localName)}) {
47       return FoldElementalIntrinsic<T, T, T>(
48           context, std::move(funcRef), *callable);
49     } else {
50       context.messages().Say(
51           "%s(real(kind=%d), real(kind%d)) cannot be folded on host"_en_US,
52           name, KIND, KIND);
53     }
54   } else if (name == "bessel_jn" || name == "bessel_yn") {
55     if (args.size() == 2) { // elemental
56       // runtime functions use int arg
57       using Int4 = Type<TypeCategory::Integer, 4>;
58       if (auto callable{GetHostRuntimeWrapper<T, Int4, T>(name)}) {
59         return FoldElementalIntrinsic<T, Int4, T>(
60             context, std::move(funcRef), *callable);
61       } else {
62         context.messages().Say(
63             "%s(integer(kind=4), real(kind=%d)) cannot be folded on host"_en_US,
64             name, KIND);
65       }
66     }
67   } else if (name == "abs") {
68     // Argument can be complex or real
69     if (auto *x{UnwrapExpr<Expr<SomeReal>>(args[0])}) {
70       return FoldElementalIntrinsic<T, T>(
71           context, std::move(funcRef), &Scalar<T>::ABS);
72     } else if (auto *z{UnwrapExpr<Expr<SomeComplex>>(args[0])}) {
73       if (auto callable{GetHostRuntimeWrapper<T, ComplexT>("abs")}) {
74         return FoldElementalIntrinsic<T, ComplexT>(
75             context, std::move(funcRef), *callable);
76       } else {
77         context.messages().Say(
78             "abs(complex(kind=%d)) cannot be folded on host"_en_US, KIND);
79       }
80     } else {
81       common::die(" unexpected argument type inside abs");
82     }
83   } else if (name == "aimag") {
84     return FoldElementalIntrinsic<T, ComplexT>(
85         context, std::move(funcRef), &Scalar<ComplexT>::AIMAG);
86   } else if (name == "aint" || name == "anint") {
87     // ANINT rounds ties away from zero, not to even
88     common::RoundingMode mode{name == "aint"
89             ? common::RoundingMode::ToZero
90             : common::RoundingMode::TiesAwayFromZero};
91     return FoldElementalIntrinsic<T, T>(context, std::move(funcRef),
92         ScalarFunc<T, T>([&name, &context, mode](
93                              const Scalar<T> &x) -> Scalar<T> {
94           ValueWithRealFlags<Scalar<T>> y{x.ToWholeNumber(mode)};
95           if (y.flags.test(RealFlag::Overflow)) {
96             context.messages().Say("%s intrinsic folding overflow"_en_US, name);
97           }
98           return y.value;
99         }));
100   } else if (name == "dprod") {
101     if (auto scalars{GetScalarConstantArguments<T, T>(context, args)}) {
102       return Fold(context,
103           Expr<T>{Multiply<T>{
104               Expr<T>{std::get<0>(*scalars)}, Expr<T>{std::get<1>(*scalars)}}});
105     }
106   } else if (name == "epsilon") {
107     return Expr<T>{Scalar<T>::EPSILON()};
108   } else if (name == "huge") {
109     return Expr<T>{Scalar<T>::HUGE()};
110   } else if (name == "max") {
111     return FoldMINorMAX(context, std::move(funcRef), Ordering::Greater);
112   } else if (name == "merge") {
113     return FoldMerge<T>(context, std::move(funcRef));
114   } else if (name == "min") {
115     return FoldMINorMAX(context, std::move(funcRef), Ordering::Less);
116   } else if (name == "real") {
117     if (auto *expr{args[0].value().UnwrapExpr()}) {
118       return ToReal<KIND>(context, std::move(*expr));
119     }
120   } else if (name == "sign") {
121     return FoldElementalIntrinsic<T, T, T>(
122         context, std::move(funcRef), &Scalar<T>::SIGN);
123   } else if (name == "tiny") {
124     return Expr<T>{Scalar<T>::TINY()};
125   }
126   // TODO: cshift, dim, dot_product, eoshift, fraction, matmul,
127   // maxval, minval, modulo, nearest, norm2, pack, product,
128   // reduce, rrspacing, scale, set_exponent, spacing, spread,
129   // sum, transfer, transpose, unpack, bessel_jn (transformational) and
130   // bessel_yn (transformational)
131   return Expr<T>{std::move(funcRef)};
132 }
133 
134 template <int KIND>
FoldOperation(FoldingContext & context,ComplexComponent<KIND> && x)135 Expr<Type<TypeCategory::Real, KIND>> FoldOperation(
136     FoldingContext &context, ComplexComponent<KIND> &&x) {
137   using Operand = Type<TypeCategory::Complex, KIND>;
138   using Result = Type<TypeCategory::Real, KIND>;
139   if (auto array{ApplyElementwise(context, x,
140           std::function<Expr<Result>(Expr<Operand> &&)>{
141               [=](Expr<Operand> &&operand) {
142                 return Expr<Result>{ComplexComponent<KIND>{
143                     x.isImaginaryPart, std::move(operand)}};
144               }})}) {
145     return *array;
146   }
147   using Part = Type<TypeCategory::Real, KIND>;
148   auto &operand{x.left()};
149   if (auto value{GetScalarConstantValue<Operand>(operand)}) {
150     if (x.isImaginaryPart) {
151       return Expr<Part>{Constant<Part>{value->AIMAG()}};
152     } else {
153       return Expr<Part>{Constant<Part>{value->REAL()}};
154     }
155   }
156   return Expr<Part>{std::move(x)};
157 }
158 
159 FOR_EACH_REAL_KIND(template class ExpressionBase, )
160 template class ExpressionBase<SomeReal>;
161 } // namespace Fortran::evaluate
162